This invention relates to cone crushers and more particularly to such crushers which have fabricated upper and lower main frames. In addition, this invention relates to such cone crushers which include anti-span mechanisms and crusher setting indicators.
Cone crushers, which are devices well known in the art, are devices which are adapted to receive large pieces of hard material such as, for example, large chunks of rock and to reduce them to a large number of smaller pieces which are of a generally uniform size. The crushers which are presently widely used in the concrete and aggregate industry have numerous characteristics which make them less than ideal. For example, such crushers must have extraordinarily strong main frames due to the fact that they are subject to extreme mechanical stresses. For this reason, among others, such crushers have generally been provided with cast frames. Although such cast frames have generally proved to be of sufficient strength, the cost of their manufacture is quite high and they are therefore, from an economic point of view, less than completely satisfactory. In an effort to overcome this negative aspect it has been proposed to fabricate the lower portion of the main frame of such a crusher from pre-formed components rather than to cast it and to thereby obtain substantial savings. An example of such a cone crusher which includes a fabricated lower main frame portion is provided in U.S. Pat. No. 3,150,839. It is noted, however, that even this patent teaches a crusher main frame structure which includes cast members, in particular, this patent teaches a structure utilizing a cast center hub. The industry, recognizing the advantages of fabricated main frames for crushers has attempted to provide main frame structures which are completely fabricated, that is, contain only plate and forged members and contain no cast members. An example of a crusher frame which is constructed from only fabricated members is provided by U.S. Pat. No. 3,843,068 which is fabricated solely from pre-formed components which are welded together. Such structures, although providing definite advantages over the earlier cast structures are nevertheless not completely satisfactory in that they frequently require great numbers of components to fullfill their function. For example, the last noted patent includes an adapter plate for permitting the mating of the center hub with the countershaft which houses the required motor drive shaft. Clearly, this results in less than a completely satisfactory solution to the problem because a greater number of prefabricated sections requires a greater number of welds. This, in turn, provides the opportunity for unsatisfactory welds and results in increased expense in that each of the welds must be (or should be) inspected either by X-ray or ultra-sonic techniques or both.
As indicated above, the function of a crusher is to provide, for subsequent use, stones, crushed rock, etc. of a uniform size. Clearly, therefore, it is important to be able to determine, prior to operation of the crusher, the magnitude of the crushed material which will be provided by the crusher unit, that is, the crusher setting. Presently known crusher setting indicators are not, however, completely satisfactory in that they are either mechanically complex and expensive or they do not provide information regarding the size of the material to be provided by the crusher with a desired degree of accuracy. It is, of course, possible to accurately and inexpensively determine the crusher setting by measuring the size of the material after it passes through the crushing chamber and is emitted from the crusher but such information is obviously of less utility than is knowledge of the crusher setting prior to operation of the crusher.
Cone crushers of the type here under discussion include a gyratory member generally referred to in the art as a mantle. Due to the construction of the crusher, the gyrating mantle has a tendency to rotate in a first direction when the crusher is not under load, that is when the crusher is not in the process of crushing material. Further, the mantle tends to rotate in a second direction, opposite to the first direction, when the crusher is under load. As is well known in the art, rotation of the mantle in the first (no load) direction is to be avoided because such rotation can cause additional and extensive wear to the expensive mantle. It is therefore quite common in the crusher art to provide what is frequently referred to as an anti-spin mechanism. The mechanisms presently known frequently are in the form of devices which absolutely bar the rotation of the mantle in the first direction while permitting the mantle to freely rotate in the second direction. The utility of such mechanisms has proved to be less than completely satisfactory because absolutely barring the rotation of the mantle in the first direction, may, under conditions where the mantle is being urged in the first direction with sufficient force, result in the destruction of components of the crusher.